#define _CRT_SECURE_NO_WARNINGS
#include <ctype.h>
#include <stdio.h>
int main()
{
	char a = 'A';
	char b = 'a';
	int ret1 =tolower(a);
	int ret2 = toupper(b);
	printf("%c\n", ret1);
	printf("%c\n", ret2);
	printf("%c\n", a);
	printf("%c\n", b);
	return 0;
}